Synthesis of the fully glycosylated cyclohexenone core of lomaiviticin A.

We describe two four-step sequences for conversion of the inexpensive reagent ethyl sorbate to either O-allyl-N,N-dimethyl-D-pyrrolosamine or O-allyl-L-oleandrose, protected forms of the 2,6-dideoxy sugar residues found in the complex bacterial metabolite lomaiviticin A. We also report a gram-scale synthesis of the highly-oxygenated cyclohexenone ring of this metabolite, and show this may be coupled with the aforementioned donors to form the bis(glycoside) 6. The longest linear sequence to 6 is nine steps.